Meibomian gland is a sebaceous gland present in the tarsal plate and has orifices around the top and bottom eyelid margins. The lipid (meibum) secreted from the meibomian gland is distributed on the eyelid margin and the outermost layer of the lacrimal fluid, and acts to suppress evaporation of lacrimal fluid, promote the stability of lacrimal fluid, promote the extension of lacrimal fluid on the eye surface, suppress outflow of lacrimal fluid from the eyelid margin onto the skin, and the like (non-patent document 1).
While meibomian gland dysfunction (MGD) is clinically used to refer to an abnormal state of meibomian gland function (non-patent document 2), it has not attracted attention clinically in general ophthalmology for the reasons that (1) inflammation and resident bacterium may or may not be involved and clinical images vary, (2) the severity varies widely from a mild case to a severe case, (3) definition and diagnostic standard have not been established heretofore, (4) only a few treatments are effective, and the like.
In fact, however, a considerable proportion of the patients who visited ophthalmological clinic with symptoms such as ocular discomfort and the like as the chief complaints was caused by MGD, and many patients are considered to have been suffering from reduced QOL. Although MGD is a clinically important disease, the study thereof has not been conducted much for the above-mentioned reasons and, as the situation stands, an effective therapeutic agent has not been found as yet.
On the other hand, while an ophthalmic composition containing activated vitamin D (patent document 1), an external preparation containing vitamin Ds, vitamin Ks (patent document 2), a therapeutic agent for dry eye, which contains activated vitamin D3 (patent document 3) and the like have been reported, none of them describe or suggest that activated vitamin D3 has a therapeutic or improving effect on meibomian gland dysfunction.